<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script>
function boom()
{
  document.getElementById("c").setAttribute('span', 2);
  document.getElementById("cg").setAttribute('span', 2);
}
</script>
</head>
<body onload="boom();">
<table><colgroup id="cg"><col span="3" id="c" /></colgroup></table>
</body>
</html>
